Optical Detector Module and a Method for Operating the Same

ABSTRACT

An optical detector module can be used to implement proximity sensing function by detecting ambient light outside of the optical detector module in accordance with a first detection threshold. An optical detector module can be further used to implement other active functions such as material detection (e.g., skin) or depth-sensing by emitting one or more optical signals (e.g., light pulses at a specific wavelength) and detecting the reflected optical signals relative to a second and/or third detection threshold. The disclosure provides technical solutions for actively monitoring detection threshold(s) of an optical detector module to achieve better power management. In some embodiments, such solutions are useful for photodetectors having a wide sensing bandwidth, such as a photodetector formed in germanium or a photodetector comprising an absorption region comprising germanium.

RELATED APPLICATIONS

The present application claims filing benefit of U.S. Provisional PatentApplication Ser. No. 63/183,064, having a filing date of May 3, 2021,and U.S. Provisional Patent Application Ser. No. 63/270,018, having afiling date of Oct. 20, 2021. All such applications are incorporatedherein by reference in its entirety.

FIELD

The present disclosure relates generally to an optical detector moduleand a method for operating the same.

BACKGROUND

Sensors are being used in many applications, such as smartphones,wearables, robotics, and autonomous vehicles, etc. for objectrecognition, image enhancement, material recognition, and other relevantapplications.

SUMMARY

Aspects and advantages of embodiments of the present disclosure will beset forth in part in the following description, or may be learned fromthe description, or may be learned through practice of the embodiments.

One example aspect of the present disclosure is directed to a method foroperating an optical detector module. The method includes (i) detecting,by a receiver unit of the optical detector module, an ambient light. Themethod also includes (ii) acquiring, by a processor, a first integralvalue from the receiver unit corresponding to the ambient light. Themethod also includes (iii) determining, by the processor, whether thefirst integral value satisfies a first threshold condition. The methodalso includes (iv) in response to determining that the first integralvalue does not satisfy the first threshold condition, sending, by acontroller, one or more first control signals to (1) disable a firstlight source of the transmitter unit of the optical detector moduleconfigured to emit a first optical signal with a first peak wavelengthand disable a second light source of the transmitter unit of the opticaldetector module configured to emit a second optical signal with a secondpeak wavelength, or (2) lower a detecting frequency of the receiverunit. The method also includes (v) in response to determining that thefirst integral value satisfies the first threshold condition, sending,by the controller, one or more second control signals to enable thefirst light source of the transmitter unit of the optical detectormodule to emit the first optical signal with the first peak wavelength.

In some implementations, v) further includes (a) acquiring, by theprocessor, a second integral value from the receiver unit correspondingto the first optical signal. In addition, (v) includes (b) determining,by the processor, whether the second integral value satisfies a secondthreshold condition. In addition, (v) includes (c) in response todetermining that the second integral value satisfies the secondthreshold condition, sending, by the controller, one or more thirdcontrol signals to enable the second light source of the transmitterunit of the optical detector module to emit the second optical signalwith the second peak wavelength, wherein the first peak wavelength isdifferent from the second peak wavelength. In addition, (v) includes (d)in response to determining that the second integral value does notsatisfy the second threshold condition, sending, by the controller, oneor more fourth control signals to (1) disable the second light source or(2) lower the detecting frequency of the receiver unit.

In some implementations, lowering the detecting frequency of thereceiver unit further comprises (1) lowering a frequency of the firstoptical signal emitted by the first light source or lowering a frequencyof the second optical signal emitted by the second light source; or (2)lowering an operating frequency of the receiver unit.

In some implementations, (a) further includes obtaining, by theprocessor and from the receiver unit, a first background integral valuecorresponding to ambient light within a first reference time slot beforea first target time slot. In addition, (a) further includes obtaining,by the processor and from the receiver unit, a first foreground integralvalue corresponding to a combination of ambient light and the firstoptical signal within the first target time slot. In addition, (a)further includes obtaining, by the processor and from the receiver unit,a second background integral value corresponding to ambient light withina second reference time slot after the first target time slot. Inaddition, (a) further includes determining, by the processor, an averageof the first background integral value and the second backgroundintegral value to obtain an averaged background integral value. Inaddition, (a) further includes adjusting, by the processor and based onthe averaged background integral value, the first foreground integralvalue to determine the second integral value.

In some implementations, (a) further includes obtaining, by theprocessor and from the receiver unit, a first group of backgroundintegral values corresponding to ambient light within multiple firstreference time slots before a first target time slot. In addition, (a)further includes obtaining, by the processor and from the receiver unit,a first foreground integral value corresponding to a combination ofambient light and the first optical signal within the first target timeslot. In addition, (a) further includes obtaining, by the processor andfrom the receiver unit, a second group of background integral valuescorresponding to ambient light within multiple second reference timeslots after the first target time slot. In addition, (a) furtherincludes determining, by the processor, an average of the first group ofbackground integral values and the second group of background integralvalues to obtain an averaged background integral value. In addition, (a)further includes adjusting, by the processor and based on the averagedbackground integral value, the first foreground integral value todetermine the second integral value.

In some implementations, (c) further includes detecting, by the receiverunit of the optical detector module, the second optical signal with thesecond peak wavelength. In addition, (c) further includes acquiring, bythe processor, a third integral value corresponding to the secondoptical signal. In addition, (c) further includes determining, by theprocessor, a comparison of the second integral value and the thirdintegral value. In addition, (c) further includes identifying, by theprocessor and based on the comparison, a material of a target.

In some implementations, acquiring the third integral value furtherincludes obtaining, by the processor and from the receiver unit, a thirdbackground integral value corresponding to ambient light within a thirdreference time slot before a second target time slot. Acquiring thethird integral value further includes obtaining, by the processor andfrom the receiver unit, a second foreground integral value correspondingto a combination of ambient light and the second optical signal withinthe second target time slot. Acquiring the third integral value furtherincludes obtaining, by the processor and from the receiver unit, afourth background integral value corresponding to ambient light within afourth reference time slot after the second target time slot. Acquiringthe third integral value further includes determining, by the processor,an average of the third background integral value and the fourthbackground integral value to obtain an averaged background integralvalue. Acquiring the third integral value further includes adjusting, bythe processor and based on the averaged background integral value, thesecond foreground integral value to determine the third integral value.

In some implementations, acquiring the second integral value furtherincludes obtaining, by the processor and from the receiver unit, a firstbackground integral value corresponding to ambient light within a firstreference time slot before a first target time slot. Acquiring thesecond integral value further includes obtaining, by the processor andfrom the receiver unit, a first foreground integral value correspondingto a combination of ambient light and the first optical signal withinthe first target time slot. Acquiring the second integral value furtherincludes obtaining, by the processor and from the receiver unit, asecond background integral value corresponding to ambient light within asecond reference time slot after the first target time slot. Acquiringthe second integral value further includes determining, by theprocessor, an average of the first background integral value and thesecond background integral value to obtain an averaged backgroundintegral value. Acquiring the second integral value further includesadjusting, by the processor and based on the averaged backgroundintegral value, the first foreground integral value to determine thesecond integral value.

In some implementations, acquiring the third integral value furtherincludes obtaining, by the processor and from the receiver unit, a thirdgroup of background integral values corresponding to ambient lightwithin multiple third reference time slots before a second target timeslot. Acquiring the third integral value further includes obtaining, bythe processor and from the receiver unit, a second foreground integralvalue corresponding to a combination of ambient light and the secondoptical signal within the second target time slot. Acquiring the thirdintegral value further includes obtaining, by the processor and from thereceiver unit, a fourth group of background integral valuescorresponding to ambient light within multiple fourth reference timeslots after the second target time slot. Acquiring the third integralvalue further includes determining, by the processor, an average of thethird group of background integral values and the fourth group ofbackground integral values to obtain an averaged background integralvalue. Acquiring the third integral value further includes adjusting, bythe processor and based on the averaged background integral value, thesecond foreground integral value to determine the second integral value.

In some implementations, acquiring the second integral value furtherincludes obtaining, by the processor and from the receiver unit, a firstgroup of background integral values corresponding to ambient lightwithin multiple first reference time slots before a first target timeslot. Acquiring the second integral value further includes obtaining, bythe processor and from the receiver unit, a first foreground integralvalue corresponding to a combination of ambient light and the firstoptical signal within the first target time slot. Acquiring the secondintegral value further includes obtaining, by the processor and from thereceiver unit, a second group of background integral valuescorresponding to ambient light within multiple second reference timeslots after the first target time slot. Acquiring the second integralvalue further includes determining, by the processor, an average of thefirst group of background integral values and the second group ofbackground integral values to obtain an averaged background integralvalue. Acquiring the second integral value further includes adjusting,by the processor and based on the averaged background integral value,the first foreground integral value to determine the second integralvalue.

In some implementations, the material comprises human skin, wood orfabric.

In some implementations, the method also includes determining, by theprocessor, whether the material of the target is skin. In response todetermining that the material of the target is not skin, the methodincludes repeating steps (i), (ii), (iii), (iv) and (v).

In some implementations, the method also includes determining, by theprocessor, whether the material of the target is skin. In response todetermining that the material of the target is skin, the method includesimplementing a health sensing function comprising at least one ofdetermining a heartrate, determining a temperature, or determining anoxygen saturation level.

In some implementations, the method also includes determining, by theprocessor, whether the material of the target is skin. In response todetermining that the material of the target is skin, the method includesimplementing a biometric authentication operation.

In some implementations, the method also includes determining, by theprocessor, whether the material of the target is skin. In response todetermining that the material of the target is skin, the method includesadjusting one or more operating parameters of the optical detectormodule to reduce power expended by the optical detector module.

Another example aspect of the present disclosure is directed to anoptical detector module that includes a receiver unit, a transmitterunit comprising a first light source configured to emit first opticalsignal with first peak wavelength and a second light source configuredto emit second light with second peak wavelength, a processor inelectrical communication with the receiver unit, and a controller inelectrical communication with the receiver unit, the processor and/orthe transmitter unit. The optical detector module is configured toperform operations. The operations include detecting, by the receiverunit of the optical detector module, an ambient light. The operationsalso include acquiring, by the processor, a first integral value fromthe receiver unit corresponding to the ambient light. The operationsalso include determining, by the processor, whether the first integralvalue satisfies a first threshold condition. The operations also includein response to determining that the first integral value does notsatisfy the first threshold condition, sending, by a controller, one ormore first control signals to (1) disable a first light source of thetransmitter unit of the optical detector module and disable a secondlight source of the transmitter unit of the optical detector module, or(2) lower a detecting frequency of the receiver unit. The operationsalso include in response to determining that the first integral valuesatisfies the first threshold condition, sending, by the controller, oneor more second control signals to enable the first light source of thetransmitter unit of the optical detector module to emit the firstoptical signal with the first peak wavelength.

In some implementations, the optical detector module is configured foruse in a wireless earbud.

In some implementations, the optical detector module is configured foruse in a wearable computing device.

Another example aspect of the present disclosure is related to a methodfor operating an optical detector module. The method includes (i)obtaining, by a processor and from a receiver unit of the opticaldetector module, a first background integral value corresponding toambient light within a first reference time slot before a first targettime slot. The method also includes (ii) obtaining, by the processor andfrom the receiver unit, a first foreground integral value correspondingto a combination of ambient light and target optical signal within thefirst target time slot. The method also includes (iii) obtaining, by theprocessor and from the receiver unit, a second background integral valuecorresponding to ambient light within a second reference time slot afterthe first target time slot. The method also includes (iv) determining,by the processor, an average of the first background integral value andthe second background integral value to obtain an averaged backgroundintegral value. The method also includes (v) adjusting, by the processorand based on the averaged background integral value, the firstforeground integral value to determine the second integral value.

Another example aspect of the present disclosure is related to a methodfor operating an optical detector module comprising multiple receiverunits and multiple transmitter units corresponding to the multiplereceiver units respectively. The method includes (i) detecting, by atleast one of the receiver units of the optical detector module, anambient light. The method also includes (ii) acquiring, by a processor,a first integral value from the receiver unit corresponding to theambient light. The method also includes (iii) determining, by theprocessor, whether the first integral value satisfies a first thresholdcondition. The method also includes (iv) in response to determining thatthe first integral value does not satisfy the first threshold condition,sending, by a controller, one or more first control signals to (1)disable one or more light sources of the multiple transmitter unitsconfigured to emit an optical signal or (2) lower a detecting frequencyof each of the receiver units. The method also includes (v) in responseto determining that the first integral value satisfies the firstthreshold condition, sending, by the controller, one or more secondcontrol signals to enable one or more of the light sources of themultiple transmitter units of the optical detector module to emit thefirst optical signal with the first peak wavelength.

In some implementations, (v) further includes acquiring, by theprocessor, a second integral value from one of the receiver unitscorresponding to the first optical signal. In addition, (v) includesdetermining, by the processor, whether the second integral valuesatisfies a second threshold condition. In addition, (v) includes inresponse to determining that the second integral value satisfies thesecond threshold condition, sending, by the controller, one or morefourth control signals to (1) enable the one or more of the lightsources of the multiple transmitter units. In addition, (v) alsoincludes in response to determining that the second integral value doesnot satisfy the second threshold condition, sending, by the controller,one or more third control signals to disable at least one of the lightsources or (2) lower the detecting frequency of the receiver unitcorresponding to the at least one of the light sources.

Another example aspect of the present disclosure is directed to apixelated wideband sensor pixelated wideband sensor. The pixelatedwideband sensor includes a carrier and a pixel array supported by thecarrier and comprising multiple pixels. Each pixel includes a firstphotodetector unit comprising a first photodetector configured toreceive a first optical signal within a first wavelength range and togenerate photo-carriers in response to the first optical signal. Eachpixel also includes a second photodetector unit comprising a secondphotodetector configured to receive at least a second optical signalwithin a second wavelength range and to generate photo-carriers inresponse to the second optical signal, wherein the first wavelengthrange is outside a visible range and the second wavelength range iswithin the visible range. Each pixel also includes a light source arraycomprising multiple light sources surrounding the pixel array.

In some implementations of the pixelated wideband sensor, the multiplelight sources include light-emitting diodes or vertical-cavitysurface-emitting lasers.

In some implementations, the pixelated wideband sensor also includes anintegrated circuit layer between the pixel array and the carrier, andthe integrated circuit layer comprises a control circuit configured tocontrol the pixel array.

In some implementations of the pixelated wideband sensor, the integratedcircuit layer includes one or more drivers configured to control thelight source array, and the integrated circuit layer is surrounded byand electrically coupled to the light source array.

In some implementations of the pixelated wideband sensor, the pixelarray is a two-dimensional array.

In some implementations of the pixelated wideband sensor, the firstphotodetector includes a first absorption region composed of a firstmaterial comprising germanium, and the second photodetector includes RGBphotodetectors composed of a second material comprising silicon.

In some implementations of the pixelated wideband sensor, the secondphotodetector includes at least one of the blue photodetector, greenphotodetector or the red photodetector.

In some implementations of the pixelated wideband sensor, at least oneof the first photodetector unit or the second photodetector unit is atleast partially embedded in a substrate.

Another example aspect of the present disclosure is directed to apixelated wideband sensor assembly including multiple pixelated widebandsensors. Each of the pixelated wideband sensors includes a carrier and apixel array supported by the carrier and comprising multiple pixels.Each pixel includes a first photodetector unit comprising a firstphotodetector configured to receive a first optical signal within afirst wavelength range and to generate photo-carriers in response to thefirst optical signal. Each pixel also includes a second photodetectorunit comprising a second photodetector configured to receive at least asecond optical signal within a second wavelength range and to generatephoto-carriers in response to the second optical signal. The firstwavelength range is outside a visible range and the second wavelengthrange is within the visible range. Each pixel also includes a lightsource array comprising multiple light sources surrounding the pixelarray.

In some implementations of the pixelated wideband sensor assembly, thepixelated wideband sensors are arranged in a two-dimensional array.

In some implementations of the pixelated wideband sensor assembly, themultiple light sources comprise light-emitting diodes or vertical-cavitysurface-emitting lasers.

In some implementations, the pixelated wideband sensor assembly furtherincludes an integrated circuit layer between the pixel array and thecarrier, wherein the integrated circuit layer comprises a controlcircuit configured to control the pixel array.

In some implementations of the pixelated wideband sensor assembly, theintegrated circuit layer includes one or more drivers configured tocontrol the light source array, and the integrated circuit layer issurrounded by and electrically coupled to the light source array.

In some implementations of the pixelated wideband sensor assembly, thepixel array is a two-dimensional array.

In some implementations of the pixelated wideband sensor assembly, thefirst photodetector comprises a first absorption region comprising afirst material comprising germanium, and the second photodetectorcomprises RGB photodetectors comprising a second material comprisingsilicon.

In some implementations of the pixelated wideband sensor assembly, thesecond photodetector includes at least one of the blue photodetector,green photodetector or the red photodetector.

In some implementations of the pixelated wideband sensor assembly, atleast one of the first photodetector unit or the second photodetectorunit is at least partially embedded in a substrate.

Another example aspect of the present disclosure is directed to apixelated wideband sensor. The pixelated wideband sensor includes apixel array comprising multiple pixels. Each pixel includes a firstphotodetector unit comprising a first photodetector configured toreceive a first optical signal within a first wavelength range and togenerate photo-carriers in response to the first optical signal. Eachpixel also includes a second photodetector unit comprising a secondphotodetector configured to receive at least a second optical signalwithin a second wavelength range and to generate photo-carriers inresponse to the second optical signal, wherein the first wavelengthrange is outside a visible range and the second wavelength range iswithin the visible range. Each pixel also includes a light source arraycomprising multiple light sources and configured to emit light toward atarget, wherein the light source array is disposed under the pixelarray. Each pixel also includes a shielding layer between the lightsource array and the pixel array and configured to block the lightemitted from the light sources from being absorbed by the firstphotodetector unit and the second photodetector unit.

In some implementations of the pixelated wideband sensor assembly, themultiple light sources comprise light-emitting diodes or vertical-cavitysurface-emitting lasers.

In some implementations, the pixelated wideband sensor assembly furtherincludes an integrated circuit layer between the pixel array and theshielding layer, wherein the integrated circuit layer comprises acontrol circuit configured to control the pixel array.

In some implementations of the pixelated wideband sensor, the pixelarray is a two-dimensional array.

In some implementations of the pixelated wideband sensor assembly, thefirst photodetector comprises a first absorption region comprisinggermanium, and the second photodetector comprises RGB photodetectorscomprising silicon.

In some implementations, the second photodetector includes at least oneof the blue photodetector, the green photodetector or the redphotodetector.

In some implementations of the pixelated wideband sensor assembly, atleast one of the first photodetector unit or the second photodetectorunit is at least partially embedded in a substrate.

Other example aspects of the present disclosure are directed to systems,methods, apparatuses, sensors, computing devices, tangiblenon-transitory computer-readable media, and memory devices related tothe described technology.

These and other features, aspects and advantages of various embodimentswill become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the present disclosure, and together with thedescription, serve to explain the related principles.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisapplication will become more readily appreciated by reference to thefollowing detailed description, when taken in conjunction with theaccompanying drawings, wherein:

FIG. 1 illustrates a schematic diagram of the optical detector module,according to some embodiments.

FIG. 2A through FIG. 2E illustrate flow charts of a method for operatingthe optical detector module, according to some embodiments.

FIG. 3A through FIG. 3E illustrate timing diagrams of optical detectormodule operated by the method, according to some embodiments.

FIG. 4 illustrates a flow chart of the method for operating the opticaldetector module, according to some embodiments.

FIG. 5 illustrates a schematic diagram of the optical detector module,according to some embodiments.

FIG. 6 illustrates a flow chart of the method for operating the opticaldetector module, according to some embodiments.

FIG. 7A illustrates a top view of exemplary embodiments of a pixelatedwideband sensor.

FIG. 7B illustrates exemplary embodiments of a pixel.

FIG. 7C illustrates exemplary embodiments of a pixel.

FIG. 7D illustrates a cross-sectional view of exemplary embodiments of apixelated wideband sensor along an A-A′ in FIG. 7A.

FIG. 7E a cross-sectional view of exemplary embodiments of a pixelatedwideband sensor along an A-A′ in FIG. 7A.

FIG. 8 illustrates exemplary embodiments of a pixel where the firstphotodetector unit and the second photodetector unit are associated withthe same substrate.

FIG. 9 illustrates exemplary embodiments of a pixelated wideband sensorassembly.

FIG. 10A illustrates a top view of exemplary embodiments of a pixelatedwideband sensor.

FIG. 10B illustrates exemplary embodiments of a pixelated widebandsensor along a B-B′ in FIG. 10A.

DETAILED DESCRIPTION

An optical detector module can be used to implement proximity sensingfunction by detecting ambient light outside of the optical detectormodule. An optical detector module can be further used to implementother active functions such as material detection (e.g., skin) ordepth-sensing by emitting one or more optical signals (e.g., lightpulses at a specific wavelength) and detecting the reflected opticalsignals. As more functions are implemented in an optical detectormodule, power management for the optical detector module becomesimportant. The disclosure provides technical solutions for activelymonitoring detection threshold(s) of an optical detector module toachieve better power management. In some embodiments, such solutions areuseful for photodetectors having a wide sensing bandwidth, such as aphotodetector formed in germanium or a photodetector comprising anabsorption region comprising germanium.

FIG. 1 illustrates an optical detector module 10. The optical detectormodule 10 includes a receiver unit 100, a transmitter unit 200, aprocessor 300 in electrical communication with the receiver unit 100,and a controller 400 in electrical communication with the receiver unit100, the processor 300, and/or the transmitter unit 200. In someembodiments, the transmitter unit 200 includes a first light source 201configured to emit a first optical signal with a first peak wavelengthand a second light source 202 configured to emit a second optical signalwith a second peak wavelength. In some embodiments, the first peakwavelength or the second peak wavelength is in an NIR or SWIR wavelengthrange equal to or greater than 700 nm, such as 850 nm, 940 nm, 1050 nm,1064 nm, 1310 nm, 1350 nm, 1450 nm, or 1550 nm or any suitablewavelength range. In some embodiments, the first peak wavelength isdifferent from the second peak wavelength. In some embodiments, thefirst peak wavelength is substantially 1050 nm, and the second peakwavelength is substantially 1450 nm. In some embodiments, the receiverunit 100 includes one or more photodetectors (e.g., germaniumphotodetector) configured to generate photo-carriers in response toreceiving an incoming optical signal.

FIG. 2A through FIG. 2E illustrate flow charts of a method for operatingthe optical detector module 10. FIG. 3A through FIG. 3E illustratetiming diagrams of the optical detector module 10 operated by themethod, according to some embodiments. In some embodiments, asillustrated in FIG. 3A, the processor 300 of the optical detector module10 may measure multiple time periods A1 through A13 from time slot T0through T13, where an ambient light always exists and the receiver unit100 is on during those time periods A1 though A13. The processor 300acquires an integral value from the receiver unit 100 corresponding toeach time period. The first light source 201 and/or the second lightsource 202 can be controlled to be selectively turned on by thecontroller 400 based on the determination by the processor 300 asdescribed in detail below.

In some embodiments, as illustrated in FIG. 3B, the processor 300 of theoptical detector module 10 may measure multiple time periods B1 throughB13 from time slot T0 through T13, where an ambient light always exists.The processor 300 acquires an integral value from the receiver unit 100corresponding to the time period where the receiver unit 100 is on. Insome embodiments, the detecting frequency of the receiver unit 100 maybe controlled by the controller 400 based on the determination by theprocessor 300 as described in detail below.

In some embodiments, as illustrated in FIG. 3C, the processor 300 of theoptical detector module 10 may measure multiple time periods C1 throughC10 from time slot T0 through T10, where an ambient light always existsand the receiver unit 100 is on during those time periods C1 though C10.The processor 300 acquires an integral value from the receiver unit 100corresponding to each time period. In some embodiments, based on thedetermination by the processor 300 as described in detail below, thefrequency of the first optical signal emitted by the first light source201 may be controlled so as to control the detecting frequency of thereceiver unit 100.

In some embodiments, as illustrated in FIG. 3D, the processor 300 of theoptical detector module 10 may measure multiple time periods D1 throughD10 from time slot T0 through T10, where an ambient light always existsand the receiver unit 100 is on during those time periods D1 though D10.The processor 300 acquires an integral value from the receiver unit 100corresponding to each time period. In some embodiments, the integralvalue in solid line in target time slot (e.g., T1 through T2, T3 throughT4, T5 through T6, T7 through T8, T9 through T10) may be obtained byadjusting a foreground integral value in dotted line as described indetail below.

In some embodiments, as illustrated in FIG. 3E, the processor 300 of theoptical detector module 10 may measure multiple time periods E1 throughE10 from time slot T0 through T10, where an ambient light always existsand the receiver unit 100 is on during those time periods E1 though E10.The processor 300 acquires an integral value from the receiver unit 100corresponding to each time period. In some embodiments, the integralvalue in solid line in target time slot (e.g., T1 through T2, T3 throughT4, T5 through T6, T7 through T8, T9 through T10) may be obtained byadjusting a foreground integral value in dotted line as described indetail below.

In some embodiments, along with the description of FIG. 2A through FIG.2E, the timing diagrams as illustrated in FIG. 3A through FIG. 3E areexample embodiments for describing some sequences of the steps ofoperating the optical detector module 10, the arrangement of the timeslots should not be limited to the arrangement shown in FIG. 3A throughFIG. 3E. For example, in some embodiments, the time period A4 in FIG. 3Amay be inserted between the time period E1 the time period E2, betweenthe time period E3 the time period E4, time period E5 the time periodE6, time period E7 the time period E8, and time period E9 the timeperiod E10.

Referring to S1 in FIG. 2A, the optical detector module 10 detects, bythe receiver unit 100, an ambient light. For example, the ambient lightcan be stray light from the environment, where the wavelength(s) of thestray light may or may not match the operating wavelength of the firstlight source 201 or the second light source 202.

Referring to S3 in FIG. 2A, the optical detector module 10 acquires, bythe processor 300, a first integral value from the receiver unit 100corresponding to the ambient light. For example, referring to FIG. 3A,the integral values in time periods A1, A3, A9, A11, A12, A13 correspondto the ambient light because neither the first light source 201 nor thesecond light source 202 is on during those periods.

Referring to S5 in FIG. 2A, in some embodiments, the optical detectormodule 10 may determine, by the processor 300, whether the firstintegral value satisfies a first threshold condition. For example,referring to FIG. 3A, the processor 300 may determine whether the firstintegral value (e.g., integral value of A1, A3, A9, A11, A12, A13) islower than a first value Va.

In some embodiments, the first value Va comprises a predetermined value.In other embodiments, the first value Va comprises a dynamicallydetermined value that can be refined and/or adjusted periodically basedon various operating parameters (e.g., environmental conditions,personalized applications, etc.)

Referring to S6 in FIG. 2A, in some embodiments, in response todetermining that the first integral value does not satisfy the firstthreshold condition (e.g. the first integral value exceeds the firstvalue Va), the optical detector module 10 may send, by the controller400, one or more first control signals to disable the first light source201 of the transmitter unit 200 of the optical detector module 10configured to emit the first optical signal with the first peakwavelength, and disable the second light source 202 of the transmitterunit 200 of the optical detector module 10 configured to emit the secondoptical signal with the second peak wavelength. Referring to FIG. 3A asan example, during time period A11, the first integral valuecorresponding to the ambient light is above the first value Va, theprocessor 300 determines that the first integral value does not satisfythe first threshold condition, which may further mean the ambient lightis enough or the receiver unit 100 is not in proximity with an object.As the result, the controller 400 sends one or more first controlsignals to disable both the first light source 201 and the second lightsource 202 during time period A12.

In some other embodiments, in response to determining that the firstintegral value does not satisfy the first threshold condition (e.g., thefirst integral value exceeds the first value Va), the optical detectormodule 10 may send, by the controller 400, one or more first controlsignals to lower the detecting frequency or detecting time of thereceiver unit 100. Referring to FIG. 3B as an example, the receiver unit100 may be turned on and off every other cycle. In some embodiments,lower the detecting frequency of the receiver unit 100 may includelowering an operating frequency or operating time of the receiver unit100 such as reducing the turn-on time of the receiver unit 100, forexample, time period B12 to time period B13 compared with the timeperiod B1 through time period B3 and time period B6 through time periodB9. In some embodiments, lowering the operating frequency or operatingtime of the receiver unit 100 may include increasing the turn-off timeof the receiver unit 100, for example, time period B9 through timeperiod B11 compared with time period B4 through time period B5.

Referring to S7 in FIG. 2A, in some embodiments, in response todetermining that the first integral value satisfies the first thresholdcondition (e.g., the first integral value is equal or lower than thefirst value Va), the optical detector module 10 may send, by thecontroller 400, one or more second control signals to enable the firstlight source 201 of the transmitter unit 200 of the optical detectormodule 10 to emit the first optical signal with the first peakwavelength. Referring to FIG. 3A as an example, during time period A1,the first integral value corresponding to the ambient light is below thefirst value Va, the processor 300 determines that the first integralvalue satisfies the first threshold condition, which may further meanthe receiver unit 100 is in proximity with an object or the ambientlight is weak. As the result, the controller 400 enables the first lightsource 201 to emit the first optical signal during time period A2.

According to the present disclosure, since the first light source 201 isenabled based on a threshold condition (e.g., the first thresholdcondition) regarding the ambient light, the optical module 10 canbenefit from power saving. In other words, when an ambient light isstrong enough, which fails to satisfy the first threshold condition, thefirst light source(s) and the second light source(s) may be set to asleep mode for power saving, or the operating frequency of the receiverunit can be lower for power saving.

Referring to S9 in FIG. 2A, in some embodiments, in response todetermining that the first integral value satisfies the first thresholdcondition (e.g., the first integral value is equal or lower than thefirst value Va), the optical detector module 10 may acquire, by theprocessor 300, a second integral value (e.g., integral value of timeperiod A2, A4, A6, A8, A10 in FIG. 3A) from the receiver unit 100corresponding to the first optical signal and ambient light received bythe receiver unit 100.

In some embodiments, the second integral value may be adjusted based ona collection of the ambient light and/or reflected light over time,thereby averaging the ambient light to get a smoother or calibratedbackground value, so as to acquire the second integral valuecorresponding to the first optical signal more accurately. Some exampleembodiments of S9 in FIG. 2A are described in FIG. 2B, FIG. 2C and FIG.3D below.

FIG. 2B shows one example flow chart for acquiring the second integralvalue. Referring to S911 in FIG. 2B and referring to FIG. 3D, in someembodiments, the optical detector module 10 may obtain, by the processor300 and from the receiver unit 100, a first background integral value(e.g., the integral value of D1 in FIG. 3D) corresponding to ambientlight within a first reference time slot (e.g., T0 through T1 in FIG.3D) before a first target time slot (e.g., T1 through T2 in FIG. 3D). Insome embodiments, in the reference time slot (e.g., the first referencetime slot and the second reference time slot mentioned below), neitherthe first light source 201 nor the second light source 202 is on. Insome embodiments, in the first target time slot, the first light source201 is on and the second light source 202 is off.

Referring to S912 in FIG. 2B and referring to FIG. 3D, the opticaldetector module 10 may further obtain, by the processor 300 and from thereceiver unit 100, a first foreground integral value (e.g., integralvalue shown in dotted line of D2 in FIG. 3D) corresponding to acombination of ambient light and the first optical signal within thefirst target time slot (e.g., T1 through T2 in FIG. 3D).

Referring to S913 in FIG. 2B and referring to FIG. 3D, the opticaldetector module 10 may further obtain, by the processor 300 and from thereceiver unit 100, a second background integral value (e.g., theintegral value of D3 in FIG. 3D) corresponding to ambient light within asecond reference time slot (e.g., T2 through T3 in FIG. 3D) after thefirst target time slot (e.g., T1 through T2 in FIG. 3D).

Referring to S914 in FIG. 2B and referring to FIG. 3D, the opticaldetector module 10 may further determine, by the processor 300, anaverage of the first background integral value (e.g., the integral valueof D1 in FIG. 3D) and the second background integral value (e.g., theintegral value of D3 in FIG. 3D) to obtain an averaged backgroundintegral value.

Referring to S915 in FIG. 2B and referring to FIG. 3D, the opticaldetector module 10 may further adjust, by the processor 300 and based onthe averaged background integral value, the first foreground integralvalue (e.g., integral value shown in dotted line of D2 in FIG. 3D) todetermine the second integral value (e.g., integral value shown in solidline of D2 in FIG. 3D). Accordingly, the second integral value shown insolid line corresponds to the first optical signal more accurately.

FIG. 2C shows another example flow chart for acquiring the secondintegral value. Referring to S921 in FIG. 2C and referring to FIG. 3D,the optical detector module 10 may obtain by the processor 300 and fromthe receiver unit 100, a first group of background integral values(e.g., the integral values of D1, D3, and D5 in FIG. 3D) correspondingto ambient light within multiple first reference time slots (e.g., T0through T1, T2 through T3, and T4 through T5 in FIG. 3D) before a firsttarget time slot (e.g., T5 through T6 in FIG. 3D). In some embodiments,as mentioned before, in the reference time slot (e.g., the firstreference time slot and the second reference time slot), neither thefirst light source 201 nor the second light source 202 is on.

Referring to S922 in FIG. 2C and referring to FIG. 3D, the opticaldetector module 10 may further obtain, by the processor 300 and from thereceiver unit 100, a first foreground integral value (e.g., integralvalue shown in dotted line of D6 in FIG. 3D) corresponding to acombination of ambient light and the first optical signal within thefirst target time slot (e.g., T5 through T6 in FIG. 3D).

Referring to S923 in FIG. 2C and referring to FIG. 3D, the opticaldetector module 10 may further obtain, by the processor 300 and from thereceiver unit 100, a second group of background integral values (e.g.,the integral values of D7, D9 in FIG. 3D) corresponding to ambient lightwithin multiple second reference time slots (e.g., T6 through T7, T8through T9 in FIG. 3D) after the first target time slot (e.g., T5through T6 in FIG. 3D).

Referring to S924 in FIG. 2C and referring to FIG. 3D, the opticaldetector module 10 may further determine, by the processor 300, anaverage of the first group of background integral values (e.g., theintegral values of D1, D3, D5 in FIG. 3D) and the second group ofbackground integral values (e.g., the integral values of D7, D9 in FIG.3D) to obtain an averaged background integral value.

Referring to S925 in FIG. 2C and referring to FIG. 3D, the opticaldetector module 10 may further adjust, by the processor 300 and based onthe averaged background integral value, the first foreground integralvalue (e.g., integral value shown in dotted line of D6 in FIG. 3D) todetermine the second integral value (e.g., integral value shown in solidline of D6 in FIG. 3D). Accordingly, the second integral value shown insolid line corresponds to the first optical signal more accurately.

Referring back to S11 in FIG. 2A and referring to FIG. 3A, the opticaldetector module 10 determines, by the processor 300, whether the secondintegral value satisfies a second threshold condition, e.g., whether thesecond integral value (e.g., integral value of A2, A4, A6, A8, A10 inFIG. 3A) equals or exceeds a second value Vb. In some embodiments, thesecond value Vb comprises a predetermined value. In other embodiments,the second value Vb comprises a dynamically determined value that can berefined and/or adjusted periodically based on various operatingparameters (e.g., environmental conditions, personalized applications,etc.)

In S13, in some embodiments, in response to determining that the secondintegral value satisfies the second threshold condition (e.g. the secondintegral value equals or exceeds the second value Vb), the opticaldetector module 10 may send, by the controller 400, one or more thirdcontrol signals to enable the second light source 202 of the transmitterunit 200 of the optical detector module 10 to emit the second opticalsignal with the second peak wavelength, where the first peak wavelengthis different from the second peak wavelength. Referring to FIG. 3A as anexample, during time period A4, the second integral value correspondingto the first optical signal and the ambient light is above the secondvalue Vb, the processor 300 determines that the second integral valuesatisfies the second threshold condition, which may further mean thereceiver unit 100 is in proximity with the object. As the result, thecontroller 400 enables the second light source 202 during time periodA5.

Referring to S12 in FIG. 2A, in some embodiments, in response todetermining that the second integral value does not satisfy the secondthreshold condition (e.g., the second integral value is lower than thesecond value Vb), the optical detector module 10 may send, by thecontroller, one or more fourth control signals to disable the secondlight source 202. Referring to FIG. 3A as an example, during time periodA8, the second integral value corresponding to the first optical signaland the ambient light is below the second value Vb, the processor 300determines that the second integral value does not satisfy the secondthreshold condition, which may further mean the object may be moved awayfrom the receiver unit 100. As a result, the controller 400 disables thesecond light source 202 during time period A9 to save power.

In some other embodiments, in response to determining that the secondintegral value does not satisfy the second threshold condition (e.g.,the second integral value is lower than the second value Vb), theoptical detector module 10 may send, by the controller, one or morefourth control signals to lower the detecting frequency of the receiverunit 100. As mentioned above, referring to FIG. 3B as an example, lowerthe detecting frequency of the receiver unit 100 may include thereceiver unit 100 turned on and off every other cycle. In someembodiments, lower the detecting frequency of the receiver unit 100 mayinclude lowering an operating frequency or operating time of thereceiver unit 100 such as reducing the turn-on time of the receiver unit100, for example, time period B12 to time period B13 compared with thetime period B1 through time period B3 and time period B6 through timeperiod B9. In some embodiments, lower the detecting frequency of thereceiver unit 100 may include increasing the turn-off time of thereceiver unit 100, for example, time period B9 through time period B11compared with time period B4 through time period B5.

In some embodiments, referring to FIG. 3A and FIG. 3C as anotherexample, if the optical detector module 10 is disposed under strongambient light, after multiple consecutive time periods where the firstintegral values equal or exceed the first value Va, e.g., time periodA11 through A13 and C1, the first light source 201 may be turned on bythe processor 300 (e.g., time period C2 in FIG. 3C) so as to activelydetermine whether the second integral value satisfies the secondthreshold condition. In some embodiments, the first light source 201 maybe turned on and off every other cycle so as to save power.

In some embodiments, the optical signal is reflected from a targetobject. For example, if an object is approaching the optical detectormodule 10, the second integral value may equal or exceed a predeterminedvalue (e.g., second value Vb), which satisfies the second thresholdcondition. Accordingly, the second light source 202 will be enabledafter receiving the third control signal.

According to the present disclosure, since the second light source 202is enabled based on a threshold condition regarding the optical signalemitted by the first light source 201, the optical detector module 10can benefit from power saving. In other words, the second light source202 may be in a sleep mode when the second integral value fails tosatisfy the second threshold condition. Therefore, the optical detectormodule 10 can further benefit from power saving.

Referring to S15 in FIG. 2A, in some embodiments, in response todetermining that the second integral value satisfies the secondthreshold condition (e.g., the second integral value equals or exceedsthe second value Vb), the optical detector module 10 may detect, by thereceiver unit 100 of the optical detector module, the second opticalsignal with the second peak wavelength.

Referring to S17 in FIG. 2A, in some embodiments, the optical detectormodule 10 may acquire, by the processor 300, a third integral valuecorresponding to the second optical signal.

Referring to S19 in FIG. 2A, in some embodiments, the optical detectormodule 10 may determine, by the processor 300, a comparison of thesecond integral value and the third integral value. In some embodiments,a comparison of the second integral value and the third integral valuemay be implemented as a ratio of the second integral value and the thirdintegral value. In some other embodiments, a comparison of the secondintegral value and the third integral value may be implemented as adifferent relational combination of the second integral value and thethird integral value (e.g., a difference between the second integralvalue and the third integral value).

Referring to S21 in FIG. 2A, in some embodiments, the optical detectormodule 10 may identify, by the processor 300 and based on the comparison(or other suitable relationship between the second integral value andthe third integral value), a material of a target. In some embodiments,the material identified in S21 comprises human skin, wood or fabric. Forexample, if the ratio of the second integral value and the thirdintegral value is between 0.8 and 1.2, the material can be determined tobe human skin.

Identifying a material of a target can be useful for a variety ofapplications. In an example application concerning robotic vacuums orother robots that maneuver along a ground surface, the target cancorrespond to the ground surface. Determining whether the ground surfaceis carpet, hard floor, or other material can help optimize functionalityof a robotic apparatus relative to navigation, cleaning, or otherfunctions.

In another application concerning food freshness analysis, the targetcan correspond to a consumable food item (e.g., a fruit, vegetable,coffee bean, etc.). Detection of water ingredients or water compositionof a consumable food item can help to characterize the materialaccording to a range of desired freshness of the food item.

In yet another application concerning object detection, the target cancorrespond to an object detected in an environment of a robot such as aself-driving vehicle. Detection of a material associated with a targetobject can help to determine a classification of the object as avehicle, a pedestrian, or other item.

In a still further application concerning smart wireless earbuds, thedisclosed technology can be used to detect when a wireless earbud is putinto a human ear and when it is pulled out of a human ear. For example,the determination (e.g., at S5) whether the first integral valuesatisfies the first threshold condition can be based on ambient lightsignals that effectively monitor whether an optical detector modulewithin a smart wireless earbud is in or near an aperture. After it isdetermined that the earbud is in or near an aperture, a subsequentdetermination (e.g., based on S11-S23) can be employed to determinewhether the earbud is proximate to human skin. If the material of atarget is determined at S23 to be human skin, then it is likely that thewireless earbud has been placed into a human ear as opposed to beingplaced on a table, into an earbud case, or proximate to a differentsurface. Verification of proper placement of a smart wireless earbud canbe employed to provide benefits such as power saving, performanceenhancement, and the like.

Referring to S23 in FIG. 2A, the optical detector module 10 maydetermine, by the processor 300 and based on the identification in S21of the material of the target, whether the material of the target isskin.

Referring to S25 in FIG. 2A, in response to determining that thematerial of the target is not skin, the optical detector module 10 mayschedule a next detection. Scheduling a next detection can includerouting the method back to detecting, by the receiver unit 100 of theoptical detector module 10, an ambient light (e.g., S1 in FIG. 2A).

Referring to S27 in FIG. 2A, in response to determining at S23 that thematerial of the target is skin, the optical detector module 10 mayexecute, by the processor 300, a different function control.

In some embodiments, the function control executed at S27 can includeimplementing a low power control mode within the optical detector module10. For example, a low power control mode can include shifting one ormore of the multiple light sources (e.g., first light source 201 and/orsecond light source 202 in FIG. 1) into a sleep mode for power savings.In another example, a low power control mode can additionally oralternatively include reducing the operating frequency of the receiverunit 100 so that less operating power is expended for at least a periodof time.

In some embodiments, the function control executed at S27 can includelowering a current level utilized by the transmitter unit Tx (e.g.,transmitter unit 200 in FIG. 1). Because a determination has been madeat S23 that the material of the target is skin, there is no need to usehigh current for additional sensing operations.

In some embodiments, the function control executed at S27 can includeenabling, by the processor 300, a health sensing function. For example,a health sensing function can include determining a health parameter ofa human operator of a device (e.g., fitness tracker or other wearableconsumer computing device, health monitoring device or other medicalcomputing device) that includes the optical detector module 10. Examplehealth parameters that can be determined in a health sensing function atS27 can include a heartrate or other parameter associated with aheartbeat, body temperature, saturation of peripheral oxygen level(e.g., SPO2 levels as measured by a pulse oximeter), or other healthparameters that can be determined using optical sensing technologyconfigured to discern a health parameter based on determination of theprocessor 300.

In some embodiments, enabling a health sensing function at S27 mayinvolve increasing the current level utilized by the transmitter unit(e.g., 200) and TIA gain associated with a transimpedance amplifier inthe receiver unit (e.g., 100) to obtain a more suitable signal forpurposes of implementing the health sensing function. For example, anaverage LED-On current value can be obtained by the processor 300 duringa phase of the method associated with proximity and skin detection(e.g., S21, S23 in FIG. 2A). Based on the determined average LED-Oncurrent value, operating signals can be modified during a phase of themethod associated with the health sensing function (e.g., S27 in FIG.2A). For example, a DC current can be implemented at the TIA input basedon the determined average LED-On current value. TIA gain can then beincreased to amplify the AC signal obtained during the health sensingfunction.

In some embodiments, enabling a health sensing function at S27 mayadditionally or alternatively involve increasing a sample frequency ofobtained measurements to obtain better sample resolution for purposes ofimplementing the health sensing function.

In some embodiments, the function control executed at S27 can includeexecuting a biometric authentication operation. For example, when theoptical detector module 10 is included within a device (e.g., acomputing device) operated by a human user, an authentication operationmay be executed for permitting access by the human user to some or allof the functionality of the device. Biometric authentication operationsmay include, for example, fingerprint detection, face detection, opticaldetection, or the like. Technical advantages can be realized bydetermining at S23 that the material of the target is skin beforeimplementing an authentication operation at S27. Such advantages includeimproving the success rate of proper biometric recognition andauthentication as the processor will not be fooled by looking at aphotograph of a fingerprint, face, etc.

In some embodiments, similarly to the second integral value, the thirdintegral value may be adjusted based on a collection of the ambientlight and/or reflected light over time, thereby averaging the ambientlight to get a smoother or calibrated background value, so as to acquirethe third integral value corresponding to the second optical signal moreaccurately. Some example embodiments of S17 in FIG. 2A are described inFIG. 2D, FIG. 2E and FIG. 3E below.

FIG. 2D shows one example flow chart for acquiring the third integralvalue. Referring to S17 in FIG. 2A, S1711 in FIG. 2D and FIG. 3E, insome embodiments, acquiring the third integral value at S17 in FIG. 2Afurther comprises obtaining, by the processor 300 and from the receiverunit 100, a third background integral value (e.g., the integral value ofE1 in FIG. 3E) corresponding to ambient light within a third referencetime slot (e.g., T0 through T1 in FIG. 3E) before a second target timeslot (e.g., T1 through T2 in FIG. 3E). In some embodiments, in thereference time slot (e.g., the third reference time slot and the fourthreference time slot mentioned below), neither the first light source 201nor the second light source 202 is on. In some embodiments, in thesecond target time slot, the first light source 201 is off and thesecond light source 202 is on.

Referring to S1712 in FIG. 2D and referring to FIG. 3E, in someembodiments, acquiring the third integral value at S17 further comprisesobtaining, by the processor 300 and from the receiver unit 100, a secondforeground integral value (e.g., integral value shown in dotted line ofE2 in FIG. 3E) corresponding to a combination of ambient light and thesecond optical signal within the second target time slot (e.g., T1through T2 in FIG. 3E)

Referring to S1713 in FIG. 2D and referring to FIG. 3E, in someembodiments, acquiring the third integral value at S17 further comprisesobtaining, by the processor 300 and from the receiver unit 100, a fourthbackground integral value (e.g., the integral value of E3 in FIG. 3E)corresponding to ambient light within a fourth reference time slot afterthe second target time slot (e.g., T1 through T2 in FIG. 3E).

Referring to S1714 in FIG. 2D and referring to FIG. 3E, in someembodiments, acquiring the third integral value at S17 further comprisesdetermining, by the processor 300, an average of the third backgroundintegral value (e.g., the integral value of E1 in FIG. 3E) and thefourth background integral value (e.g., the integral value of E3 in FIG.3E) to obtain an averaged background integral value.

Referring to S1715 in FIG. 2D and referring to FIG. 3E, in someembodiments, acquiring the third integral value at S17 further comprisesadjusting, by the processor 300 and based on the averaged backgroundintegral value, the second foreground integral value (e.g., integralvalue shown in dotted line of E2 in FIG. 3E) to determine the thirdintegral value (e.g., integral value shown in solid line of E2 in FIG.3E). Accordingly, the third integral value shown in solid linecorresponds to the second optical signal more accurately.

FIG. 2E shows another example flow chart for acquiring the thirdintegral value. Referring to S1721 in FIG. 2E and referring to FIG. 3E,in some embodiments, acquiring the third integral value at S17 in FIG.2A further comprises obtaining, by the processor 300 and from thereceiver unit 100, a third group of background integral values (e.g.,the integral values of E1, E3, E5 in FIG. 3E) corresponding to ambientlight within multiple third reference time slots (e.g., T0 through T1,T2 through T3, T4 through T5 in FIG. 3E) before a second target timeslot (e.g., T5 through T6 in FIG. 3E). In some embodiments, as mentionedbefore, in the reference time slot (e.g., the third reference time slotand the fourth reference time slot), neither the first light source 201nor the second light source 202 is on.

Referring to S1722 in FIG. 2E and referring to FIG. 3E, in someembodiments, acquiring the third integral value at S17 further comprisesobtaining, by the processor 300 and from the receiver unit 100, a secondforeground integral value (e.g., integral value shown in dotted line ofE6 in FIG. 3E) corresponding to a combination of ambient light and thesecond optical signal within the second target time slot (e.g., T5through T6 in FIG. 3E).

Referring to S1723 in FIG. 2E and referring to FIG. 3E, in someembodiments, acquiring the third integral value at S17 further comprisesobtaining, by the processor 300 and from the receiver unit 100, a fourthgroup of background integral values (e.g., the integral values of E7, E9in FIG. 3E) corresponding to ambient light within multiple fourthreference time slots (e.g., T6 through T7, T8 through T9 in FIG. 3E)after the second target time slot (e.g., T5 through T6 in FIG. 3E).

Referring to S1724 in FIG. 2E and referring to FIG. 3E, in someembodiments, acquiring the third integral value at S17 further comprisesdetermining, by the processor 300, an average of the third group ofbackground integral values (e.g., the integral values of E1, E3, E5 inFIG. 3E) and the fourth group of background integral values (e.g., theintegral values of E7, E9 in FIG. 3E) to obtain an averaged backgroundintegral value.

Referring to S1725 in FIG. 2E and referring to FIG. 3E, in someembodiments, acquiring the third integral value at S17 further comprisesadjusting, by the processor 300 and based on the averaged backgroundintegral value, the second foreground integral value (e.g., integralvalue shown in dotted line of E6 in FIG. 3E) to determine the thirdintegral value (e.g., integral value shown in solid line of E6 in FIG.3E) (e.g., S1725 in FIG. 2E). Accordingly, the third integral valueshown in solid line corresponds to the second optical signal moreaccurately.

It should be appreciated that the various time slots depicted in FIGS.3A-3E for calculating integral values in accordance with the disclosedtechnology correspond to one illustrative example. The signal timing andanalysis depicted in FIGS. 3A-3E utilize multiplexed time slots becausethe optical detector module 10 of FIG. 1 includes one transmitter unit(e.g., 200) including multiple light sources (e.g., first light source201 and second light source 202) and one receiver unit (e.g., 100).Although a reduced number of transmitter and receiver components can beemployed when desired for a reduction in cost and power consumption,other optical detector modules may use different signal timing analysisthan the arrangements depicted in FIGS. 3A-3E when a different number oftransmitters and receivers are utilized.

In some embodiments, the first reference time slot and the thirdreference time slot may be the same time slot, depending on thearrangement of the time slots. In some embodiments, the second referencetime slot and the fourth reference time slot may be the same slot,depending on the arrangement of the time slots.

FIG. 4 illustrates a flow chart of the method for operating the opticaldetector module, according to some embodiments. The method S30 foroperating an optical detector module 10 is disclosed. Referring to S31in FIG. 4, the method S30 comprises obtaining, by the processor 300 andfrom a receiver unit 100 of the optical detector module 10, a firstbackground integral value corresponding to ambient light within a firstreference time slot before a target time slot. In some embodiments, inthe reference time slot (e.g., the first reference time slot and thesecond reference time slot mentioned below), none of the light sources(e.g., the first light source 201 and the second light source 202) ison.

Referring to S32 in FIG. 4, the method S30 further comprises obtaining,by the processor 300 and from the receiver unit 100, a foregroundintegral value corresponding to a combination of ambient light and atarget optical signal within the target time slot.

Referring to S33 in FIG. 4, the method S30 further comprises obtaining,by the processor 300 and from the receiver unit 100, a second backgroundintegral value corresponding to ambient light within a second referencetime slot after the target time slot.

Referring to S34 in FIG. 4, the method S30 further comprisesdetermining, by the processor 300, an average of the first backgroundintegral value and the second background integral value to obtain anaveraged background integral value.

Referring to S35 in FIG. 4, the method S30 further comprises adjusting,by the processor 300 and based on the averaged background integralvalue, the foreground integral value to determine a corrected integralvalue.

According to the present disclosure, since the corrected integral valueis obtained based on multiple background integral values, the signaloutput from the optical detector module 10 is with improved signalaccuracy.

FIG. 5 illustrates an optical detector module 50 having multiplereceiver units 501 and 502 and multiple transmitter units 503 and 504corresponding to the multiple receiver units 501, 502 respectively. Eachof the multiple transmitter units 503, 504 includes a light source 5031,5041) configured to emit an optical signal with a peak wavelength. Thepeak wavelengths of the optical signals emitted by the light sources5031 and 5041 are substantially the same or different. The opticaldetector module 50 further includes a processor 505 in electricalcommunication with the receiver units 501, 502, and a controller 506 inelectrical communication with the processor 505 and the transmitterunits 503, 504. In some embodiments, the peak wavelength is in aninvisible wavelength range equal to or greater than 700 nm, such as 850nm, 940 nm, 1050 nm, 1064 nm, 1310 nm, 1350 nm, 1450 nm or 1550 nm orany suitable wavelength range. In some embodiments, each of the receiverunit 501, 502 includes one or more photodetectors configured to generatephoto-carriers in response to receiving an incoming optical signal. Insome embodiments, if the peak wavelengths of the optical signals emittedby the light sources 5031 and 5041 are different, to avoid cross talkbetween the receiver units 501 and 502, each of the receiver units 501and 502 includes an optical filter configured to pass light having awavelength range corresponding to the peak wavelength of the opticalsignals emitted by the light sources 5031 and 5041 respectively.

FIG. 6 illustrates a flow chart for operating the optical detectormodule 50. In S611, the optical detector module 50 detects, by at leastone of the receiver units (e.g., 501) of the optical detector module 50,an ambient light.

In S613, in some embodiments, the optical detector module 50 acquires,by the processor 505, a first integral value from the receiver unit(e.g., 501) corresponding to the ambient light.

In S615, in some embodiments, the optical detector module 50 determines,by the processor 505, whether the first integral value satisfies a firstthreshold condition, for example, whether the first integral value isequal or lower than a first threshold value. In some embodiments, thefirst threshold value comprises a predetermined value. In otherembodiments, the first threshold value comprises a dynamicallydetermined value that can be refined and/or adjusted periodically basedon various operating parameters (e.g., environmental conditions,personalized applications, etc.)

In S616, in response to determining that the first integral value doesnot satisfy the first threshold condition (e.g., the first integralvalue exceeds the first threshold value), the optical detector module 50sends, by a controller 506, one or more first control signals to (1)disable light sources of the multiple transmitter units 503 and/or 504or (2) lower a detecting frequency of each of the receiver units 501and/or 502.

In S617, in response to determining that the first integral valuesatisfies the first threshold condition (e.g., the first integral valueis equal or lower than the first threshold value), the optical detectormodule 50 sends, by the controller 506, one or more second controlsignals to enable one or more of the light sources 5041 and/or 5031 ofthe multiple transmitter units 503 and/or 504 of the optical detectormodule 50 to emit the first optical signal with a first peak wavelength.

In S619, in response to determining that the first integral valuesatisfies the first threshold condition (e.g., the first integral valueis equal or lower than the first threshold value), the optical detectormodule 50 may further acquire, by the processor 505, at least a secondintegral value from one of the receiver units (e.g., 501) correspondingto the first optical signal with the first peak wavelength and theambient light. In some embodiments, if multiple light sources emitteddifferent peak wavelengths are turned on based on the thresholdcondition (e.g., the first threshold condition) regarding the ambientlight, multiple integral values corresponding to different opticalsignals from the multiple receiver units 501, 502 can be obtained at thesame period of time, which improves efficiency.

In S621, the optical detector module 50 may further determines, by theprocessor 505, whether the second integral value satisfies a secondthreshold condition, for example, whether the second integral valueequal or exceeds a second threshold value.

In S623, in response to determining that the second integral valuesatisfies the second threshold condition (e.g., the second integralvalue equal or exceeds the second threshold value), the optical detectormodule 50 may send, by the controller 506, one or more third controlsignals to (1) enable another one or more of the light sources 5031and/or 5041 of the multiple transmitter units 503, 504.

In S622, in response to determining that the second integral value doesnot satisfy the second threshold condition (e.g., the second integralvalue is lower than the second threshold value), the optical detectormodule 50 may send, by the controller 506, one or more fourth controlsignals to disable at least one of the light sources 5031 and/or 5041 or(2) lower the detecting frequency of the receiver unit 502 correspondingto the at least one of the light sources 5041 and/or 5031.

According to the present disclosure, since at least one of the multiplelight sources is enabled based on a threshold condition regarding theoptical signal emitted by another light source, the optical detectormodule can benefit from power saving when at least one of the lightsources is in sleep mode or the operating frequency of the receiver unitcan be lower for power saving. By selectively controlling the lightsources, an optical detector module can be configured to illuminatelight only when necessary. This process can be iteratively refined inorder to achieve even greater realization of power reduction in anoptical detector module.

The present disclosure further provides a pixelated wideband sensor thatsupports applications for multiple wavelength ranges, including visible(e.g., wavelength range 380 nm to 780 nm, or a similar wavelength rangeas defined by a particular application), near-infrared (NIR, e.g.,wavelength range from 780 nm to 1400 nm, or a similar wavelength rangeas defined by a particular application) and short-wavelength infrared(SWIR, e.g., wavelength range from 1400 nm to 3000 nm, or a similarwavelength range as defined by a particular application) wavelengthranges. Combining multi-wavelength sensing over a wideband (e.g.,visible and NIR) can enable short-range applications such as truewireless stereo (TWS), under-display fingerprint sensing, contactless or3D fingerprint sensing, as well as camera and depth-sensing fusing on asingle module platform. In some embodiments, aspects of the technologyillustrated in FIGS. 7A-10B can be employed to implement the opticaldetector module in any one of FIGS. 1 through 5. However, otherimplementations can additionally or alternatively be employed.

FIG. 7A illustrates a top view of exemplary embodiments of a pixelatedwideband sensor. FIG. 7B illustrates exemplary embodiments of a pixel.The pixelated wideband sensor 700 a comprises a carrier (e.g., element780 in FIG. 7D, such as a PCB board or a substrate) and a pixel array720 supported by the carrier 780. The pixel array 720 comprises multiplepixels 721 and may be a two-dimensional array. Referring to FIG. 7B, themultiple pixels 721 comprises a first photodetector unit 710 and asecond photodetector unit 714. The multiple pixels 721 can be the sameor different. For example, referring to FIG. 7B, the multiple pixels 721can be the same, and each of the multiple pixels 721 includes a firstphotodetector unit 710 and a second photodetector unit 712. The firstphotodetector unit 710 includes a first photodetector 711 configured toreceive a first optical signal within a first wavelength range and togenerate photo-carriers in response to the first optical signal. In someembodiments, the first photodetector unit 710 may include multiple firstphotodetectors 711. The first wavelength range is in invisible range,for example, in IR region such as NIR region or SWIR region, forexample, not less than 800 nm (e.g., 7800 to 2500 nm or 1400 nm to 3000nm). In some embodiments, the first optical signal is reflected from atarget object. In some embodiments, the first photodetector unit 710 isconfigured for depth sensing by direct or indirect time-of-flight (TOF)method. In some other embodiments, the first photodetector unit 710 isconfigured for proximity sensing. In some other embodiments, the firstphotodetector unit 710 is configured for image sensing.

The second photodetector unit 712 comprises a second photodetector(e.g., green photodetector 714, red photodetector 715 or bluephotodetector 713) configured to receive at least a second opticalsignal within a second wavelength range and to generate photo-carriersin response to the second optical signal. The second wavelength range isin a visible range, for example, between about 380 nm and 780 nm. Insome embodiments, the second photodetector unit 712 further includes ablue photodetector 713 configured to receive an optical signal inblue-colored band such as between about 380 nm and 495 nm, a greenphotodetector 714 configured to receive an optical signal ingreen-colored band such as between about 495 nm and 570 nm, and a redphotodetector 715 configured to receive an optical signal in red-coloredband such as between about 570 nm and 780 nm. In some embodiments, thesecond photodetector unit 712 is configured for image sensing.

FIG. 7C illustrates another embodiment of pixels, where at least two ofthe multiple pixels 721 are different. For example, the pixel 721 aincludes the first photodetector unit 710 having the first photodetector711. In some embodiments, the first photodetector unit 710 may alsoinclude multiple first photodetectors 711. The pixel 721 b includes thesecond photodetector unit 712 having the blue photodetector 713, thegreen photodetector 714 and the red photodetector 715. As anotherexample, the pixel array 720 may include four pixels, where each pixelincludes a single photodetector (e.g., an IR photodetector, a redphotodetector, a blue photodetector, or a green photodetector).

FIG. 7D illustrates a cross-sectional view of exemplary embodiments of apixelated wideband sensor along an A-A′ axis as depicted in FIG. 7A.Referring to FIG. 7A and FIG. 7D, the pixelated wideband sensor 700 afurther includes a light source array 730 including multiple lightsources 731 surrounding the pixel array 720. The number of the lightsources 731 may not be limited to the number shown in FIG. 7A. Themultiple light sources 731 include light-emitting diodes orvertical-cavity surface-emitting lasers. In some embodiments, thepixelated wideband sensor 700 d is configured for a shorter-rangeapplication such as contactless or 3D fingerprint sensor or underdisplay fingerprint sensor. By multiple light sources 731 surroundingthe pixel array 720, a target object can be illuminated by more lightemitted from the multiple light sources 731 and thus more optical signalreflected from the target object can be received by the pixel array 720.In addition, providing multiple light sources 731 around the pixel array720 can advantageously help provide more homogenous distribution oflight across the pixel array 720. Better light distribution can helpavoid a situation where some pixels 721 don't receive as much reflectedlight as others within the pixel array 720.

In some embodiments, each of the light sources 731 may also include anoptical element (e.g., a passive optical element such as a mirror or agrating, or an active optical element such as a micro-electromechanicalsystem (MEMS) mirror) for changing the direction of the light emittedfrom the multiple light sources 731 so as to modify the illuminationarea of the light source array 730. In some embodiments, the pixelatedwideband sensor may be assembled with other modules for mid-rangeapplications (e.g., facial recognition) or long-range applications(e.g., object sensing in self-driving applications).

Referring to FIG. 7D, in some embodiments, the pixelated wideband sensor700 d further comprises an integrated circuit layer 740 between thepixel array 720 and the carrier 780. The integrated circuit layer 740comprises a control circuit (e.g., first, second, third, and fourthcontrol signal as mentioned below) configured to control the pixel array720 and/or a driver configured to control the light sources 731. In someembodiments, the integrated circuit layer 740 is disposed only betweenthe pixel array 720 and the carrier 780, and the pixelated widebandsensor 700 d may further include electrical connection (not shown)coupled to the light sources 731 and the driver of the integratedcircuit layer 740. In some other embodiments, the driver circuit for thelight sources 731 may be implemented on a separate chip (not shown) ormay be integrated with the light sources 731.

In some embodiments, the pixelated wideband sensor 700 d furthercomprises a bonding layer 750 between the integrated circuit layer 740and the pixel array 720. The bonding layer 750, for example, may includeinterconnects for electrical connection between the integrated circuitlayer 740 and the pixel array 720, and dielectric material forelectrical isolation between the interconnects. The driver and/or thecontrol circuit can be, for example, a complementary metal-oxidesemiconductor (CMOS) device.

In some embodiments, the pixelated wideband sensor 700 d furthercomprises optical filters 760 configured to pass light having a specificwavelength range corresponding to the photodetectors disposed below. Theoptical filters 760 may be implemented as a bandpass filter using anabsorption material, or multi-layer coating, or in-planeperiodic/aperiodic grating, etc. As an example, the bandpass filters 760a, 760 b, 760 c, and 760 d may be configured to pass light having awavelength of blue, green, red, and SWIR, respectively.

In some embodiments, the pixelated wideband sensor 700 d furthercomprises multiple lens elements 770 for focusing, collimating, orexpanding incoming optical signal into respective photodetectors below.

FIG. 7E a cross-sectional view of exemplary embodiments of a pixelatedwideband sensor along an A-A′ axis as depicted in FIG. 7A. In someembodiments, the integrated circuit layer 740 is between the lightsources 731 and the carrier 780.

In some embodiments, the first photodetector unit 710 and/or the secondphotodetector unit 712 are at least partially embedded in a substrate(e.g., silicon substrate), where the first photodetector 711 comprises afirst absorption region 833 comprising germanium, and the secondphotodetector unit 712 comprises RGB photodetectors (e.g., 713, 714, 715in FIG. 7B) comprising silicon. For example, FIG. 8 illustratesexemplary embodiments of a pixel where the first photodetector unit 710and the second photodetector unit 712 are associated with a commonsubstrate, for example, where the first photodetector unit 710 and thesecond photodetector unit 712 are at least partially embedded in asubstrate (e.g., Si substrate 814, 824). The pixel 721 includes a firstphotodetector 711 and a visible photodetector, such as greenphotodetector 714 that are formed on a common substrate. The firstphotodetector 711 and the green photodetector 714 may be separated by anisolation structure 807 such as an oxide trench.

The green photodetector 714 includes an n-Si region 812, a p+ Si region813, a p-Si region 814, an n+ Si region 815, a first gate 816. The firstgate 816 is coupled to and controlled by a first control signal. The n+Si region 815 is coupled to a first readout circuit.

The n-Si region 812 may be lightly doped with an n-dopant, e.g., about10¹⁶ cm⁻³ with phosphorus. The p+ Si region 813 may have a p+ doping,where the activated dopant concentration is as high as a fabricationprocess may achieve, e.g., about 5×10²⁰ cm⁻³ with boron. The p-Si region814 may be lightly doped with a p-dopant, e.g., about 10¹⁵ cm⁻³ withboron. The n+ Si region 815 may have an n+ doping, where the activateddopant concentration is as high as a fabrication process may achieve,e.g., about 5×10²⁰ cm⁻³ with phosphorous.

In general, the n-Si layer 812 receives an optical signal 808 andconverts the optical signal 808 into electrical signals. The opticalsignal 808 (e.g., green light) enters the n-Si region 812, where then-Si region 812 absorbs the optical signal 808 and converts the absorbedlight into free carriers. In some implementations, the optical signal808 may be filtered by optical filters (e.g., 760 in FIG. 7D). In someimplementations, a beam profile of the optical signal 808 may be shapedby a lens element (e.g., 770 in FIG. 7D).

In general, a difference between the Fermi level of the p+ Si region 813and the Fermi level of the n-Si region 812 creates an electric fieldbetween the two regions, where free electrons generated by the n-Siregion 812 are drifted to a region below the p+ Si region 813 by theelectric field. The first gate 816 may be coupled to a voltage source,for example, the first control signal may be a DC voltage signal fromthe voltage source. The first control signal controls a flow of freeelectrons from the region below the p+ Si region 813 to the n+ Si region815. For example, if a voltage of the first control signal exceeds athreshold voltage, free electrons accumulated in the region below the p+Si region 813 will drift to the n+ Si region 815.

The n+ Si region 815 may be coupled to the first readout circuit. Thefirst readout circuit may be in a three-transistor configurationconsisting of a reset gate, a source-follower, and a selection gate, orany suitable circuitry for processing free carriers. In someimplementations, the first readout circuit may be fabricated on asubstrate that is common to the green photodetector 714. For example,the first readout circuit may be included in an integrated circuit layer740 as described in reference to FIG. 7D. In some other implementations,the first readout circuit may be fabricated on another substrate andco-packaged with the green photodetector 714 via die/wafer bonding orstacking.

The first photodetector 711 includes an n-Si region 822, a p+ Si region823, a p-Si region 824, an n+ Si region 825, a second gate 826, a p+GeSi region 831, and an intrinsic GeSi region 833. The second gate 826is coupled to and controlled by a second control signal. The n+Si region825 is coupled to a second readout circuit. The n-Si region 822 may belightly doped with an n-dopant, e.g., about 10¹⁶ cm⁻³ with phosphorus.The p+ Si region 823 may have a p+ doping, where the activated dopantconcentration is as high as a fabrication process may achieve, e.g.,about 5×10²⁰ cm⁻³ with boron. The p-Si region 824 may be lightly dopedwith a p-dopant, e.g., about 10¹⁵ cm⁻³ with boron. The n+ Si region 825may have an n+ doping, where the activated dopant concentration is ashigh as a fabrication process may achieve, e.g., about 5×10²⁰ cm⁻³ withphosphorous.

In general, the intrinsic GeSi region 833 receives an optical signal 806and converts the optical signal 806 (e.g., SWIR light) into electricalsignals. In some implementations, the optical signal 806 may be filteredby a wavelength filter not shown in this figure, such as an NIR filterin the optical filters (e.g., 760 in FIG. 7D). In some implementations,a beam profile of the optical signal 806 may be shaped by a lens element(e.g., 770 in FIG. 7D).

In some implementations, a thickness of the intrinsic GeSi region 833may be between 0.05 μm to 2 μm. In some implementations, the intrinsicGeSi region 833 may include a p+ GeSi region 831. The p+ GeSi region 831may repel the photo-electrons away from the intrinsic GeSi region 833 toavoid surface recombination and thereby may increase the carriercollection efficiency. For example, the p+ GeSi region 831 may have a p+doping, where the dopant concentration is as high as a fabricationprocess may achieve, e.g., about 5×10²⁰ cm⁻³ when the intrinsic GeSiregion 833 is germanium and doped with boron.

The generated free carriers in the intrinsic GeSi region 833 may driftor diffuse into the n-Si region 822. In general, a difference betweenthe Fermi level of the p+ Si region 823 and the Fermi level of the n-Siregion 822 creates an electric field between the two regions, where freeelectrons collected from the intrinsic GeSi region 833 by the n-Siregion 822 are drifted to a region below the p+ Si region 823 by theelectric field. The second control signal may be a DC voltage signalfrom the voltage source. The second control signal 827 controls a flowof free electrons from the region below the p+ Si region 823 to the n+Si region 825. For example, if a voltage of the second control signal827 exceeds a threshold voltage, free electrons accumulated in theregion below the p+ Si region 823 will drift to the n+ Si region 825.The n+ Si region 825 may be coupled to the second readout circuit. Thesecond readout circuit may be similar to the first readout circuit.

Although not shown in FIG. 7C, in some other implementations, the greenphotodetector 714 and the first photodetector 711 may alternatively befabricated to collect holes instead of electrons. In this case, theconductivity type may be opposite. For example, the p+ Si regions 813and 823 would be replaced by n+ Si regions, the n-Si regions 812 and 813would be replaced by p-Si regions, the p-Si regions 814 and 824 would bereplaced by n-Si regions, and the n+ Si region 815 and 825 would bereplaced by p+ Si regions. Note that the drawings shown here are forillustration and working principle explanation purpose.

In some embodiments, the surface of the green photodetector 714 and thefirst photodetector 711 that receive optical signals 806 and 808 is aplanarized surface, where the intrinsic GeSi region 833 and the p+ GeSiregion 831 are embedded in an oxide layer 856. For example, the oxidelayer 856 may be formed on the p-Si region 814. A thickness of the oxidelayer 856 may be selected to be the thickness of the intrinsic GeSiregion 833. A sensor region may be formed in the oxide layer 856 byetching or any other suitable techniques. Germanium-silicon may beselectively grown in the sensor region to form the intrinsic GeSi region833. A planarized surface between the green photodetector 714 and thefirst photodetector 711 enables additional processing on the photodiodesurface and/or bonding with devices fabricated on a separate substrate.

Although not shown in FIG. 8, the pixel 721 also includes a bluephotodetector 713 and a red photodetector 715 as shown in FIG. 7B. Theblue photodetector 713 and the red photodetector 715 may includestructures similar to the green photodetector 714. In some embodiments,the blue photodetector 713 is controlled by a third control signal andcoupled to a third readout circuit to process the collected carriers. Insome embodiments, the red photodetector 715 is controlled by a fourthcontrol signal and coupled to a fourth readout circuit to process thecollected carriers. Each of the red photodetector 715 and the bluephotodetector 713 include a respective wavelength filter region (e.g.,bandpass filters 760 a, 760 b, 760 c, and 760 d) in optical filters(e.g., 760 in FIG. 7D) configured to transmit a portion of receivedlight and a respective lens element (e.g., 770 in FIG. 7D) configured tofocus the received light.

Some other example pixels associated with the same substrate aredisclosed in U.S. patent application Ser. No. 15/228,282, titled“Germanium-Silicon Light Sensing Apparatus” and filed on Aug. 4, 2016,which is fully incorporated by reference herein.

FIG. 9 illustrates exemplary embodiments of a pixelated wideband sensorassembly. The pixelated wideband sensor assembly 900 includes multiplepixelated wideband sensors 700 arranged in a two-dimensional orone-dimensional array. The pixelated wideband sensors 700 may be anyembodiments as described above. Since the pixelated wideband sensorassembly includes multiple pixelated wideband sensors 700, the pixelatedwideband sensor assembly can be easily assembled into any desireddimensions. Moreover, the total illumination area of can be larger andthe light incident on the target object can be more evenly distributed.Furthermore, the optical signal reflected from the target object can bemore easily captured by one of the pixel arrays 720 since there aremultiple pixel arrays 720 distributed in the space.

FIG. 10A illustrates a top view of exemplary embodiments of a pixelatedwideband sensor. FIG. 10B illustrates exemplary embodiments of apixelated wideband sensor along a B-B′ axis as depicted in FIG. 10A.

The pixelated wideband sensor 940 a is substantially the same as thepixelated wideband sensor 700 a as described before, the differencesbeing described below. The light source array 730 comprising multiplelight sources 731 is disposed under the pixel array 720. The pixelatedwideband sensor 940 a further includes a shielding layer 790 between thelight source array 730 and the pixel array 720. The shielding layer 790is configured to block the light emitted from the light sources 731 fromdirectly absorbed by the absorption regions of the pixel array 720. As aresult, the light 911 emitted from the light sources 731 can passthrough the light source array 730 and be incident on a target object.

In some embodiments, shielding layer 790 is composed in part of afiltering material, e.g., a polymer or other material absorbing thelight.

In some embodiments, the light emitted from the light sources 731 iswith a peak wavelength in an invisible range, such as greater than 800nm or between about 1400 nm and 3000 nm so as to avoid being absorbed bythe substrate (e.g., silicon substrate) in the pixel. In someembodiments, the second photodetector unit 712 in the pixel is ambientlight sensor.

In some embodiments, the light source in the present disclosure mayinclude one or more light emitting diodes (LEDs) or vertical-cavitysurface-emitting lasers (VCSELs) emitting an optical signal.

Various means can be configured to perform the methods, operations, andprocesses described herein. For example, any of the systems andapparatuses (e.g., optical sensing apparatus and related circuitry) caninclude unit(s) and/or other means for performing their operations andfunctions described herein. In some implementations, one or more of theunits may be implemented separately. In some implementations, one ormore units may be a part of or included in one or more other units.These means can include processor(s), microprocessor(s), graphicsprocessing unit(s), logic circuit(s), dedicated circuit(s),application-specific integrated circuit(s), programmable array logic,field-programmable gate array(s), controller(s), microcontroller(s),and/or other suitable hardware. The means can also, or alternately,include software control means implemented with a processor or logiccircuitry. For example, the means can include or otherwise be able toaccess memory such as, for example, one or more non-transitorycomputer-readable storage media, such as random-access memory, read-onlymemory, electrically erasable programmable read-only memory, erasableprogrammable read-only memory, flash/other memory device(s), dataregister(s), database(s), and/or other suitable hardware.

As used herein, the terms such as “first”, “second”, “third”, “fourth”and “fifth” describe various elements, components, regions, layersand/or sections, these elements, components, regions, layers and/orsections should not be limited by these terms. These terms may be onlyused to distinguish one element, component, region, layer or sectionfrom another. The terms such as “first”, “second”, “third”, “fourth” and“fifth” when used herein do not imply a sequence or order unless clearlyindicated by the context. The terms “photo-detecting”, “photo-sensing”,“light-detecting”, “light-sensing” and any other similar terms can beused interchangeably.

Aspects of the disclosure have been described in terms of illustrativeembodiments thereof. Numerous other embodiments, modifications, and/orvariations within the scope and spirit of the appended claims can occurto persons of ordinary skill in the art from a review of thisdisclosure. Any and all features in the following claims can be combinedand/or rearranged in any way possible. Accordingly, the scope of thepresent disclosure is by way of example rather than by way oflimitation, and the subject disclosure does not preclude inclusion ofsuch modifications, variations or additions to the present subjectmatter as would be readily apparent to one of ordinary skill in the art.Moreover, terms are described herein using lists of example elementsjoined by conjunctions such as “and,” “or,” “but,” etc. It should beunderstood that such conjunctions are provided for explanatory purposesonly. Lists joined by a particular conjunction such as “or,” forexample, can refer to “at least one of” or “any combination of” exampleelements listed therein. Also, terms such as “based on” should beunderstood as “based at least in part on”.

Those of ordinary skill in the art, using the disclosures providedherein, will understand that the elements of any of the claims discussedherein can be adapted, rearranged, expanded, omitted, combined, ormodified in various ways without deviating from the scope of the presentdisclosure. Some of the claims are described with a letter reference toa claim element for exemplary illustrated purposes and is not meant tobe limiting. The letter references do not imply a particular order ofoperations. For instance, letter identifiers such as (a), (b), (c), . .. , (i), (ii), (iii), . . . , etc. may be used to illustrate methodoperations. Such identifiers are provided for the ease of the reader anddo not denote a particular order of steps or operations. An operationillustrated by a list identifier of (a), (i), etc. can be performedbefore, after, and/or in parallel with another operation illustrated bya list identifier of (b), (ii), etc.

While the invention has been described by way of example and in terms ofa preferred embodiment, it is to be understood that the invention is notlimited thereto. On the contrary, it is intended to cover variousmodifications and similar arrangements and procedures, and the scope ofthe appended claims therefore should be accorded the broadestinterpretation so as to encompass all such modifications and similararrangements and procedures.

What is claimed is:
 1. A method for operating an optical detectormodule, comprising: (i) detecting, by a receiver unit of the opticaldetector module, an ambient light; (ii) acquiring, by a processor of theoptical detector module, a first integral value from the receiver unitcorresponding to the ambient light; (iii) determining, by the processor,whether the first integral value satisfies a first threshold condition;(iv) in response to determining that the first integral value does notsatisfy the first threshold condition, sending, by a controller of theoptical detector module, one or more first control signals to (1)disable a first light source of a transmitter unit of the opticaldetector module configured to emit a first optical signal with a firstpeak wavelength and disable a second light source of the transmitterunit of the optical detector module configured to emit a second opticalsignal with a second peak wavelength, or (2) lower a detecting frequencyof the receiver unit; and (v) in response to determining that the firstintegral value satisfies the first threshold condition, sending, by thecontroller, one or more second control signals to enable the first lightsource of the transmitter unit of the optical detector module to emitthe first optical signal with the first peak wavelength.
 2. The methodof claim 1, wherein (v) further comprises: (a) acquiring, by theprocessor, a second integral value from the receiver unit correspondingto the first optical signal; (b) determining, by the processor, whetherthe second integral value satisfies a second threshold condition; (c) inresponse to determining that the second integral value satisfies thesecond threshold condition, sending, by the controller, one or morethird control signals to enable the second light source of thetransmitter unit of the optical detector module to emit the secondoptical signal with the second peak wavelength, wherein the first peakwavelength is different from the second peak wavelength; and (d) inresponse to determining that the second integral value does not satisfythe second threshold condition, sending, by the controller, one or morefourth control signals to (1) disable the second light source or (2)lower the detecting frequency of the receiver unit.
 3. The method ofclaim 1, wherein lowering the detecting frequency of the receiver unitfurther comprises (1) lowering a frequency of the first optical signalemitted by the first light source or lowering a frequency of the secondoptical signal emitted by the second light source; or (2) lowering anoperating frequency of the receiver unit.
 4. The method of claim 2,wherein (a) further comprises: obtaining, by the processor and from thereceiver unit, a first background integral value corresponding toambient light within a first reference time slot before a first targettime slot; obtaining, by the processor and from the receiver unit, afirst foreground integral value corresponding to a combination of theambient light and the first optical signal within the first target timeslot; obtaining, by the processor and from the receiver unit, a secondbackground integral value corresponding to ambient light within a secondreference time slot after the first target time slot; determining, bythe processor, an average of the first background integral value and thesecond background integral value to obtain an averaged backgroundintegral value; and adjusting, by the processor and based on theaveraged background integral value, the first foreground integral valueto determine the second integral value.
 5. The method of claim 2,wherein (a) further comprises: obtaining, by the processor and from thereceiver unit, a first group of background integral values correspondingto ambient light within multiple first reference time slots before afirst target time slot; obtaining, by the processor and from thereceiver unit, a first foreground integral value corresponding to acombination of ambient light and the first optical signal within thefirst target time slot; obtaining, by the processor and from thereceiver unit, a second group of background integral valuescorresponding to ambient light within multiple second reference timeslots after the first target time slot; determining, by the processor,an average of the first group of background integral values and thesecond group of background integral values to obtain an averagedbackground integral value; and adjusting, by the processor and based onthe averaged background integral value, the first foreground integralvalue to determine the second integral value.
 6. The method of claim 2,wherein (c) further comprises: detecting, by the receiver unit of theoptical detector module, the second optical signal with the second peakwavelength; acquiring, by the processor, a third integral valuecorresponding to the second optical signal; determining, by theprocessor, a comparison of the second integral value and the thirdintegral value; and identifying, by the processor and based on thecomparison, a material of a target.
 7. The method of claim 6, whereinacquiring the third integral value further comprises: obtaining, by theprocessor and from the receiver unit, a third background integral valuecorresponding to the ambient light within a third reference time slotbefore a second target time slot; obtaining, by the processor and fromthe receiver unit, a second foreground integral value corresponding to acombination of ambient light and the second optical signal within thesecond target time slot; obtaining, by the processor and from thereceiver unit, a fourth background integral value corresponding toambient light within a fourth reference time slot after the secondtarget time slot; determining, by the processor, an average of the thirdbackground integral value and the fourth background integral value toobtain an averaged background integral value; and adjusting, by theprocessor and based on the averaged background integral value, thesecond foreground integral value to determine the third integral value.8. The method of claim 7, wherein acquiring the second integral valuefurther comprises: obtaining, by the processor and from the receiverunit, a first background integral value corresponding to ambient lightwithin a first reference time slot before a first target time slot;obtaining, by the processor and from the receiver unit, a firstforeground integral value corresponding to a combination of ambientlight and the first optical signal within the first target time slot;obtaining, by the processor and from the receiver unit, a secondbackground integral value corresponding to ambient light within a secondreference time slot after the first target time slot; determining, bythe processor, an average of the first background integral value and thesecond background integral value to obtain an averaged backgroundintegral value; and adjusting, by the processor and based on theaveraged background integral value, the first foreground integral valueto determine the second integral value.
 9. The method of claim 6,wherein acquiring the third integral value further comprises: obtaining,by the processor and from the receiver unit, a third group of backgroundintegral values corresponding to ambient light within multiple thirdreference time slots before a second target time slot; obtaining, by theprocessor and from the receiver unit, a second foreground integral valuecorresponding to a combination of ambient light and the second opticalsignal within the second target time slot; obtaining, by the processorand from the receiver unit, a fourth group of background integral valuescorresponding to ambient light within multiple fourth reference timeslots after the second target time slot; determining, by the processor,an average of the third group of background integral values and thefourth group of background integral values to obtain an averagedbackground integral value; and adjusting, by the processor and based onthe averaged background integral value, the second foreground integralvalue to determine the second integral value.
 10. The method of claim 9,wherein acquiring the second integral value further comprises:obtaining, by the processor and from the receiver unit, a first group ofbackground integral values corresponding to ambient light withinmultiple first reference time slots before a first target time slot;obtaining, by the processor and from the receiver unit, a firstforeground integral value corresponding to a combination of ambientlight and the first optical signal within the first target time slot;obtaining, by the processor and from the receiver unit, a second groupof background integral values corresponding to ambient light withinmultiple second reference time slots after the first target time slot;determining, by the processor, an average of the first group ofbackground integral values and the second group of background integralvalues to obtain an averaged background integral value; and adjusting,by the processor and based on the averaged background integral value,the first foreground integral value to determine the second integralvalue.
 11. The method of claim 6, wherein the material comprises humanskin, wood or fabric.
 12. The method of claim 6, further comprising:determining, by the processor, whether the material of the target isskin; and in response to determining that the material of the target isnot skin, repeating steps (i), (ii), (iii), (iv) and (v).
 13. The methodof claim 6, further comprising: determining, by the processor, whetherthe material of the target is skin; and in response to determining thatthe material of the target is skin, implementing a health sensingfunction comprising at least one of determining a heartrate, determininga temperature, or determining an oxygen saturation level.
 14. The methodof claim 6, further comprising: determining, by the processor, whetherthe material of the target is skin; and in response to determining thatthe material of the target is skin, implementing a biometricauthentication operation.
 15. The method of claim 6, further comprising:determining, by the processor, whether the material of the target isskin; and in response to determining that the material of the target isskin, adjusting one or more operating parameters of the optical detectormodule to reduce power expended by the optical detector module.
 16. Anoptical detector module, comprising: a receiver unit; a transmitterunit, comprising a first light source configured to emit first opticalsignal with first peak wavelength and a second light source configuredto emit second light with second peak wavelength; a processor inelectrical communication with the receiver unit; a controller inelectrical communication with the receiver unit, the processor and/orthe transmitter unit; wherein the optical detector module is configuredto perform operations comprising: detecting, by the receiver unit of theoptical detector module, an ambient light; acquiring, by the processor,a first integral value from the receiver unit corresponding to theambient light; determining, by the processor, whether the first integralvalue satisfies a first threshold condition; in response to determiningthat the first integral value does not satisfy the first thresholdcondition, sending, by a controller, one or more first control signalsto (1) disable a first light source of the transmitter unit of theoptical detector module and disable a second light source of thetransmitter unit of the optical detector module, or (2) lower adetecting frequency of the receiver unit; and in response to determiningthat the first integral value satisfies the first threshold condition,sending, by the controller, one or more second control signals to enablethe first light source of the transmitter unit of the optical detectormodule to emit the first optical signal with the first peak wavelength.17. The optical detector module of claim 16, wherein the opticaldetector module is configured for use in a wireless earbud.
 18. Theoptical detector module of claim 16, wherein the optical detector moduleis configured for use in a wearable computing device.
 19. A method foroperating an optical detector module comprising multiple receiver unitsand multiple transmitter units corresponding to the multiple receiverunits respectively, wherein each of the multiple transmitter unitsincludes a light source, and the method comprises: (i) detecting, by atleast one of the receiver units of the optical detector module, anambient light; (ii) acquiring, by a processor, a first integral valuefrom the receiver unit corresponding to the ambient light; (iii)determining, by the processor, whether the first integral valuesatisfies a first threshold condition; (iv) in response to determiningthat the first integral value does not satisfy the first thresholdcondition, sending, by a controller, one or more first control signalsto (1) disable at least one of the one or more light source of themultiple transmitter units or (2) lower a detecting frequency of each ofthe receiver units; and (v) in response to determining that the firstintegral value satisfies the first threshold condition, sending, by thecontroller, one or more second control signals to enable one or more ofthe light sources of the multiple transmitter units of the opticaldetector module to emit the first optical signal with the first peakwavelength.
 20. The method of claim 19, wherein (v) further comprises:acquiring, by the processor, a second integral value from one of thereceiver units corresponding to the first optical signal and the ambientlight; determining, by the processor, whether the second integral valuesatisfies a second threshold condition; in response to determining thatthe second integral value satisfies the second threshold condition,sending, by the controller, one or more fourth control signals to (1)enable another one or more of the light sources of the multipletransmitter units; and in response to determining that the secondintegral value does not satisfy the second threshold condition, sending,by the controller, one or more third control signals to disable at leastone of the light sources or (2) lower the detecting frequency of thereceiver unit corresponding to the at least one of the light sources.